GM Service Manual Online
For 1990-2009 cars only
Table 1: Body Control Module (BCM)
Table 2: Engine Control Module (ECM)

Body Control Module (BCM)

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Operating Conditions: Engine idling, A/C ON, ambient air temperature between 22-27°C (70-80°F)

A/C Request

HVAC Data

Yes, No

Yes

Afterblow

HVAC Data

Active/Inactive/Requested/Pending

Varies

Ambient Air Temperature Sensor

HVAC Data

Volts

Varies

Blower Motor Relay Command

HVAC Data

On,Off

Varies

Engine Control Module (ECM)

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Operating Conditions: Engine idling, A/C ON, ambient air temperature between 22-27°C (70-80°F)

A/C Disengage History

HVAC Data

None/A/C pressure/Engine Speed/Battery Voltage/Anti Stall/RPM Unstable/WOT/Launch Perf/Coolant Hot

Varies

A/C High Side Pressure Sensor

HVAC Data

kPa, psi

Varies

A/C High Side Pressure Sensor

HVAC Data

Volts

Varies

A/C Off For WOT

HVAC Data

Yes, No

No

A/C Pressure Disable

HVAC Data

Yes, No

No

A/C Relay Circuit Status

HVAC Data

OK/Open/Short/Invalid State

OK

A/C Relay Command

HVAC Data

Yes, No

No

A/C Request Signal

HVAC Data

Yes, No

Yes

ECT Sensor

HVAC Data

°C/°F

Varies